1NCAT(1) Ncat Reference Guide NCAT(1)
2
6 ncat - Concatenate and redirect sockets
7
9 ncat [OPTIONS...] [hostname] [port]
10
12 Ncat is a feature-packed networking utility which reads and writes data
13 across networks from the command line. Ncat was written for the Nmap
14 Project and is the culmination of the currently splintered family of
15 Netcat incarnations. It is designed to be a reliable back-end tool to
16 instantly provide network connectivity to other applications and users.
17 Ncat will not only work with IPv4 and IPv6 but provides the user with a
18 virtually limitless number of potential uses.
19 Among Ncat's vast number of features there is the ability to chain
21 Ncats together; redirection of TCP, UDP, and SCTP ports to other sites;
22 SSL support; and proxy connections via SOCKS4, SOCKS5 or HTTP proxies
23 (with optional proxy authentication as well). Some general principles
24 apply to most applications and thus give you the capability of
25 instantly adding networking support to software that would normally
26 never support it.
27
29 Ncat 7.93 ( https://nmap.org/ncat )
30 Usage: ncat [options] [hostname] [port]
31 Options taking a time assume seconds. Append 'ms' for milliseconds,
33 's' for seconds, 'm' for minutes, or 'h' for hours (e.g. 500ms).
34 -4 Use IPv4 only
35 -6 Use IPv6 only
36 -U, --unixsock Use Unix domain sockets only
37 --vsock Use vsock sockets only
38 -C, --crlf Use CRLF for EOL sequence
39 -c, --sh-exec <command> Executes the given command via /bin/sh
40 -e, --exec <command> Executes the given command
41 --lua-exec <filename> Executes the given Lua script
42 -g hop1[,hop2,...] Loose source routing hop points (8 max)
43 -G <n> Loose source routing hop pointer (4, 8, 12, ...)
44 -m, --max-conns <n> Maximum <n> simultaneous connections
45 -h, --help Display this help screen
46 -d, --delay <time> Wait between read/writes
47 -o, --output <filename> Dump session data to a file
48 -x, --hex-dump <filename> Dump session data as hex to a file
49 -i, --idle-timeout <time> Idle read/write timeout
50 -p, --source-port port Specify source port to use
51 -s, --source addr Specify source address to use (doesn't affect -l)
52 -l, --listen Bind and listen for incoming connections
53 -k, --keep-open Accept multiple connections in listen mode
54 -n, --nodns Do not resolve hostnames via DNS
55 -t, --telnet Answer Telnet negotiations
56 -u, --udp Use UDP instead of default TCP
57 --sctp Use SCTP instead of default TCP
58 -v, --verbose Set verbosity level (can be used several times)
59 -w, --wait <time> Connect timeout
60 -z Zero-I/O mode, report connection status only
61 --append-output Append rather than clobber specified output files
62 --send-only Only send data, ignoring received; quit on EOF
63 --recv-only Only receive data, never send anything
64 --no-shutdown Continue half-duplex when receiving EOF on stdin
65 --allow Allow only given hosts to connect to Ncat
66 --allowfile A file of hosts allowed to connect to Ncat
67 --deny Deny given hosts from connecting to Ncat
68 --denyfile A file of hosts denied from connecting to Ncat
69 --broker Enable Ncat's connection brokering mode
70 --chat Start a simple Ncat chat server
71 --proxy <addr[:port]> Specify address of host to proxy through
72 --proxy-type <type> Specify proxy type ("http", "socks4", "socks5")
73 --proxy-auth <auth> Authenticate with HTTP or SOCKS proxy server
74 --proxy-dns <type> Specify where to resolve proxy destination
75 --ssl Connect or listen with SSL
76 --ssl-cert Specify SSL certificate file (PEM) for listening
77 --ssl-key Specify SSL private key (PEM) for listening
78 --ssl-verify Verify trust and domain name of certificates
79 --ssl-trustfile PEM file containing trusted SSL certificates
80 --ssl-ciphers Cipherlist containing SSL ciphers to use
81 --ssl-servername Request distinct server name (SNI)
82 --ssl-alpn ALPN protocol list to use
83 --version Display Ncat's version information and exit
84 See the ncat(1) manpage for full options, descriptions and usage examples
86
89 Ncat operates in one of two primary modes: connect mode and listen
90 mode. Other modes, such as the HTTP proxy server, act as special cases
91 of these two. In connect mode, Ncat works as a client. In listen mode
92 it is a server.
93 In connect mode, the hostname and port arguments tell what to connect
95 to. hostname is required, and may be a hostname or IP address. If port
96 is supplied, it must be a decimal port number. If omitted, it defaults
97 to 31337.
98 In listen mode, hostname and port control the address the server will
100 bind to. Both arguments are optional in listen mode. If hostname is
101 omitted, it defaults to listening on all available addresses over IPv4
102 and IPv6. If port is omitted, it defaults to 31337.
103
105 -4 (IPv4 only)
106 Force the use of IPv4 only.
107 -6 (IPv6 only)
109 Force the use of IPv6 only.
110 -U, --unixsock (Use Unix domain sockets)
112 Use Unix domain sockets rather than network sockets. This option
113 may be used on its own for stream sockets, or combined with --udp
114 for datagram sockets. A description of -U mode is in the section
115 called “UNIX DOMAIN SOCKETS”.
116 -u, --udp (Use UDP)
118 Use UDP for the connection (the default is TCP).
119 --sctp (Use SCTP)
121 Use SCTP for the connection (the default is TCP). SCTP support is
122 implemented in TCP-compatible mode.
123 --vsock (Use AF_VSOCK sockets)
125 Use AF_VSOCK sockets rather than the default TCP sockets (Linux
126 only). This option may be used on its own for stream sockets or
127 combined with --udp for datagram sockets. A description of --vsock
128 mode is in the section called “AF_VSOCK SOCKETS”.
129
131 -g hop1[,hop2,...] (Loose source routing)
132 Sets hops for IPv4 loose source routing. You can use -g once with a
133 comma-separated list of hops, use -g multiple times with single
134 hops to build the list, or combine the two. Hops can be given as IP
135 addresses or hostnames.
136 -G ptr (Set source routing pointer)
138 Sets the IPv4 source route “pointer” for use with -g. The argument
139 must be a multiple of 4 and no more than 28. Not all operating
140 systems support setting this pointer to anything other than four.
141 -p port, --source-port port (Specify source port)
143 Set the port number for Ncat to bind to.
144 -s host, --source host (Specify source address)
146 Set the address for Ncat to bind to.
147
149 See the section called “ACCESS CONTROL OPTIONS” for information on
150 limiting the hosts that may connect to the listening Ncat process.
151 -l, --listen (Listen for connections)
153 Listen for connections rather than connecting to a remote machine
154 -m numconns, --max-conns numconns (Specify maximum number of
156 connections)
157 The maximum number of simultaneous connections accepted by an Ncat
158 instance. 100 is the default (60 on Windows).
159 -k, --keep-open (Accept multiple connections)
161 Normally a listening server accepts only one connection and then
162 quits when the connection is closed. This option makes it accept
163 multiple simultaneous connections and wait for more connections
164 after they have all been closed. It must be combined with --listen.
165 In this mode there is no way for Ncat to know when its network
166 input is finished, so it will keep running until interrupted. This
167 also means that it will never close its output stream, so any
168 program reading from Ncat and looking for end-of-file will also
169 hang.
170 --broker (Connection brokering)
172 Allow multiple parties to connect to a centralised Ncat server and
173 communicate with each other. Ncat can broker communication between
174 systems that are behind a NAT or otherwise unable to directly
175 connect. This option is used in conjunction with --listen, which
176 causes the --listen port to have broker mode enabled.
177 --chat (Ad-hoc “chat server”)
179 The --chat option enables chat mode, intended for the exchange of
180 text between several users. In chat mode, connection brokering is
181 turned on. Ncat prefixes each message received with an ID before
182 relaying it to the other connections. The ID is unique for each
183 connected client. This helps distinguish who sent what.
184 Additionally, non-printing characters such as control characters
185 are escaped to keep them from doing damage to a terminal.
186
188 --ssl (Use SSL)
189 In connect mode, this option transparently negotiates an SSL
190 session with an SSL server to securely encrypt the connection. This
191 is particularly handy for talking to SSL enabled HTTP servers, etc.
192 In server mode, this option listens for incoming SSL connections,
194 rather than plain untunneled traffic.
195 In UDP connect mode, this option enables Datagram TLS (DTLS). This
197 is not supported in server mode.
198 --ssl-verify (Verify server certificates)
200 In client mode, --ssl-verify is like --ssl except that it also
201 requires verification of the server certificate. Ncat comes with a
202 default set of trusted certificates in the file ca-bundle.crt.
203 Some operating systems provide a default list of trusted
204 certificates; these will also be used if available. Use
205 --ssl-trustfile to give a custom list. Use -v one or more times to
206 get details about verification failures. Ncat does not check for
207 revoked certificates.
208 This option has no effect in server mode.
210 --ssl-cert certfile.pem (Specify SSL certificate)
212 This option gives the location of a PEM-encoded certificate files
213 used to authenticate the server (in listen mode) or the client (in
214 connect mode). Use it in combination with --ssl-key.
215 --ssl-key keyfile.pem (Specify SSL private key)
217 This option gives the location of the PEM-encoded private key file
218 that goes with the certificate named with --ssl-cert.
219 --ssl-trustfile cert.pem (List trusted certificates)
221 This option sets a list of certificates that are trusted for
222 purposes of certificate verification. It has no effect unless
223 combined with --ssl-verify. The argument to this option is the name
224 of a PEM file containing trusted certificates. Typically, the file
225 will contain certificates of certification authorities, though it
226 may also contain server certificates directly. When this option is
227 used, Ncat does not use its default certificates.
228 --ssl-ciphers cipherlist (Specify SSL ciphersuites)
230 This option sets the list of ciphersuites that Ncat will use when
231 connecting to servers or when accepting SSL connections from
232 clients. The syntax is described in the OpenSSL ciphers(1) man
233 page, and defaults to
234 ALL:!aNULL:!eNULL:!LOW:!EXP:!RC4:!MD5:@STRENGTH
235 --ssl-servername name (Request distinct server name)
237 In client mode, this option sets the TLS SNI (Server Name
238 Indication) extension, which tells the server the name of the
239 logical server Ncat is contacting. This is important when the
240 target server hosts multiple virtual servers at a single underlying
241 network address. If the option is not provided, the TLS SNI
242 extension will be populated with the target server hostname.
243 --ssl-alpn ALPN list (Specify ALPN protocol list)
245 This option allows you to specify a comma-separated list of
246 protocols to send via the Application-Layer Protocol Negotiation
247 (ALPN) TLS extension. Not supported by all versions of OpenSSL.
248
250 --proxy host[:port] (Specify proxy address)
251 Requests proxying through host:port, using the protocol specified
252 by --proxy-type.
253 If no port is specified, the proxy protocol's well-known port is
255 used (1080 for SOCKS and 3128 for HTTP). When specifying an IPv6
256 HTTP proxy server using the IP address rather than the hostname,
257 the square-bracket notation (for example [2001:db8::1]:8080) MUST
258 be used to separate the port from the IPv6 address. If the proxy
259 requires authentication, use --proxy-auth.
260 --proxy-type proto (Specify proxy protocol)
262 In connect mode, this option requests the protocol proto to connect
263 through the proxy host specified by --proxy. In listen mode, this
264 option has Ncat act as a proxy server using the specified protocol.
265 The currently available protocols in connect mode are http
267 (CONNECT), socks4 (SOCKSv4), and socks5 (SOCKSv5). The only server
268 currently supported is http. If this option is not used, the
269 default protocol is http.
270 --proxy-auth user[:pass] (Specify proxy credentials)
272 In connect mode, gives the credentials that will be used to connect
273 to the proxy server. In listen mode, gives the credentials that
274 will be required of connecting clients. For use with --proxy-type
275 http or --proxy-type socks5, the form should be username:password.
276 For --proxy-type socks4, it should be a username only.
277 These credentials can be alternatively passed onto Ncat by setting
279 environment variable NCAT_PROXY_AUTH, which reduces the risk of the
280 credentials being captured in process logs. (Option --proxy-auth
281 takes precedence.)
282 --proxy-dns type (Specify where to resolve proxy destination)
284 In connect mode, it provides control over whether proxy destination
285 hostnames are resolved by the remote proxy server or locally, by
286 Ncat itself. Possible values for type are:
287 local - Hostnames are resolved locally on the Ncat host. Ncat exits
289 with error if the hostname cannot be resolved.
290 remote - Hostnames are passed directly onto the remote proxy
292 server. This is the default behavior.
293 both - Hostname resolution is first attempted on the Ncat host.
295 Unresolvable hostnames are passed onto the remote proxy server.
296 none - Hostname resolution is completely disabled. Only a literal
298 IPv4 or IPv6 address can be used as the proxy destination.
299 Local hostname resolution generally respects IP version specified
301 with options -4 or -6, except for SOCKS4, which is incompatible
302 with IPv6.
303
305 -e command, --exec command (Execute command)
306 Execute the specified command after a connection has been
307 established. The command must be specified as a full pathname. All
308 input from the remote client will be sent to the application and
309 responses sent back to the remote client over the socket, thus
310 making your command-line application interactive over a socket.
311 Combined with --keep-open, Ncat will handle multiple simultaneous
312 connections to your specified port/application like inetd. Ncat
313 will only accept a maximum, definable, number of simultaneous
314 connections controlled by the -m option. By default this is set to
315 100 (60 on Windows).
316 -c command, --sh-exec command (Execute command via sh)
318 Same as -e, except it tries to execute the command via /bin/sh.
319 This means you don't have to specify the full path for the command,
320 and shell facilities like environment variables are available.
321 --lua-exec file (Execute a .lua script)
323 Runs the specified file as a Lua script after a connection has been
324 established, using a built-in interpreter. Both the script's
325 standard input and the standard output are redirected to the
326 connection data streams.
327 All exec options add the following variables to the child's
329 environment:
330 NCAT_REMOTE_ADDR, NCAT_REMOTE_PORT
332 The IP address and port number of the remote host. In connect mode,
333 it's the target's address; in listen mode, it's the client's
334 address.
335 NCAT_LOCAL_ADDR, NCAT_LOCAL_PORT
337 The IP address and port number of the local end of the connection.
338 NCAT_PROTO
340 The protocol in use: one of TCP, UDP, and SCTP.
341
343 --allow host[,host,...] (Allow connections)
344 The list of hosts specified will be the only hosts allowed to
345 connect to the Ncat process. All other connection attempts will be
346 disconnected. In case of a conflict between --allow and --deny,
347 --allow takes precedence. Host specifications follow the same
348 syntax used by Nmap.
349 --allowfile file (Allow connections from file)
351 This has the same functionality as --allow, except that the allowed
352 hosts are provided in a new-line delimited allow file, rather than
353 directly on the command line.
354 --deny host[,host,...] (Deny connections)
356 Issue Ncat with a list of hosts that will not be allowed to connect
357 to the listening Ncat process. Specified hosts will have their
358 session silently terminated if they try to connect. In case of a
359 conflict between --allow and --deny, --allow takes precedence. Host
360 specifications follow the same syntax used by Nmap.
361 --denyfile file (Deny connections from file)
363 This is the same functionality as --deny, except that excluded
364 hosts are provided in a new-line delimited deny file, rather than
365 directly on the command line.
366
368 These options accept a time parameter. This is specified in seconds by
369 default, though you can append ms, s, m, or h to the value to specify
370 milliseconds, seconds, minutes, or hours.
371 -d time, --delay time (Specify line delay)
373 Set the delay interval for lines sent. This effectively limits the
374 number of lines that Ncat will send in the specified period. This
375 may be useful for low-bandwidth sites, or have other uses such as
376 coping with annoying iptables --limit options.
377 -i time, --idle-timeout time (Specify idle timeout)
379 Set a fixed timeout for idle connections. If the idle timeout is
380 reached, the connection is terminated.
381 -w time, --wait time (Specify connect timeout)
383 Set a fixed timeout for connection attempts.
384
386 -o file, --output file (Save session data)
387 Dump session data to a file
388 -x file, --hex-dump file (Save session data in hex)
390 Dump session data in hex to a file.
391 --append-output (Append output)
393 Issue Ncat with --append-ouput along with -o and/or -x and it will
394 append the resulted output rather than truncating the specified
395 output files.
396 -v, --verbose (Be verbose)
398 Issue Ncat with -v and it will be verbose and display all kinds of
399 useful connection based information. Use more than once (-vv,
400 -vvv...) for greater verbosity.
401
403 -C, --crlf (Use CRLF as EOL)
404 This option tells Ncat to convert LF line endings to CRLF when
405 taking input from standard input. This is useful for talking to
406 some stringent servers directly from a terminal in one of the many
407 common plain-text protocols that use CRLF for end-of-line.
408 -h, --help (Help screen)
410 Displays a short help screen with common options and parameters,
411 and then exits.
412 --recv-only (Only receive data)
414 If this option is passed, Ncat will only receive data and will not
415 try to send anything.
416 --send-only (Only send data)
418 If this option is passed, then Ncat will only send data and will
419 ignore anything received. This option also causes Ncat to close the
420 network connection and terminate after EOF is received on standard
421 input.
422 --no-shutdown (Do not shutdown into half-duplex mode)
424 If this option is passed, Ncat will not invoke shutdown on a socket
425 after seeing EOF on stdin. This is provided for
426 backward-compatibility with OpenBSD netcat, which exhibits this
427 behavior when executed with its '-d' option.
428 -n, --nodns (Do not resolve hostnames)
430 Completely disable hostname resolution across all Ncat options,
431 such as the destination, source address, source routing hops, and
432 the proxy. All addresses must be specified numerically. (Note that
433 resolution of proxy destinations is controlled separately via
434 option --proxy-dns.)
435 -t, --telnet (Answer Telnet negotiations)
437 Handle DO/DONT WILL/WONT Telnet negotiations. This makes it
438 possible to script Telnet sessions with Ncat.
439 --version (Display version)
441 Displays the Ncat version number and exits.
442
444 The -U option (same as --unixsock) causes Ncat to use Unix domain
445 sockets rather than network sockets. Unix domain sockets exist as an
446 entry in the filesystem. You must give the name of a socket to connect
447 to or to listen on. For example, to make a connection,
448 ncat -U ~/unixsock
450 To listen on a socket:
452 ncat -l -U ~/unixsock
454 Listen mode will create the socket if it doesn't exist. The socket will
456 continue to exist after the program ends.
457 Both stream and datagram domain sockets are supported. Use -U on its
459 own for stream sockets, or combine it with --udp for datagram sockets.
460 Datagram sockets require a source socket to connect from. By default, a
461 source socket with a random filename will be created as needed, and
462 deleted when the program ends. Use the --source with a path to use a
463 source socket with a specific name.
464
466 The --vsock option causes Ncat to use AF_VSOCK sockets rather than
467 network sockets. A CID must be given instead of a hostname or IP
468 address. For example, to make a connection to the host,
469 ncat --vsock 2 1234
471 To listen on a socket:
473 ncat -l --vsock 1234
475 Both stream and datagram domain sockets are supported, but socket type
477 availability depends on the hypervisor. Use --vsock on its own for
478 stream sockets, or combine it with --udp for datagram sockets.
479
481 Connect to example.org on TCP port 8080.
482 ncat example.org 8080
483 Listen for connections on TCP port 8080.
485 ncat -l 8080
486 Redirect TCP port 8080 on the local machine to host on port 80.
488 ncat --sh-exec "ncat example.org 80" -l 8080 --keep-open
489 Bind to TCP port 8081 and attach /bin/bash for the world to access
491 freely.
492 ncat --exec "/bin/bash" -l 8081 --keep-open
493 Bind a shell to TCP port 8081, limit access to hosts on a local
495 network, and limit the maximum number of simultaneous connections to 3.
496 ncat --exec "/bin/bash" --max-conns 3 --allow 192.168.0.0/24 -l
497 8081 --keep-open
498 Connect to smtphost:25 through a SOCKS4 server on port 1080.
500 ncat --proxy socks4host --proxy-type socks4 --proxy-auth joe
501 smtphost 25
502 Connect to smtphost:25 through a SOCKS5 server on port 1080.
504 ncat --proxy socks5host --proxy-type socks5 --proxy-auth joe:secret
505 smtphost 25
506 Create an HTTP proxy server on localhost port 8888.
508 ncat -l --proxy-type http localhost 8888
509 Send a file over TCP port 9899 from host2 (client) to host1 (server).
511 HOST1$ ncat -l 9899 > outputfile
512 HOST2$ ncat HOST1 9899 < inputfile
514 Transfer in the other direction, turning Ncat into a “one file” server.
516 HOST1$ ncat -l 9899 < inputfile
517 HOST2$ ncat HOST1 9899 > outputfile
519
521 The exit code reflects whether a connection was made and completed
522 successfully. 0 means there was no error. 1 means there was a network
523 error of some kind, for example “Connection refused” or “Connection
524 reset”. 2 is reserved for all other errors, like an invalid option or a
525 nonexistent file.
526
528 Like its authors, Ncat isn't perfect. But you can help make it better
529 by sending bug reports or even writing patches. If Ncat doesn't behave
530 the way you expect, first upgrade to the latest version available from
531 https://nmap.org. If the problem persists, do some research to
532 determine whether it has already been discovered and addressed. Try
533 Googling the error message or browsing the nmap-dev archives at
534 https://seclists.org/.
535 Read this full manual page as well. If nothing comes of this, mail a
537 bug report to <dev@nmap.org>. Please include everything you have
538 learned about the problem, as well as what version of Ncat you are
539 running and what operating system version it is running on. Problem
540 reports and Ncat usage questions sent to dev@nmap.org are far more
541 likely to be answered than those sent to Fyodor directly.
542 Code patches to fix bugs are even better than bug reports. Basic
544 instructions for creating patch files with your changes are available
545 at https://svn.nmap.org/nmap/HACKING. Patches may be sent to nmap-dev
546 (recommended) or to Fyodor directly.
547
549 • Chris Gibson <chris@linuxops.net>
550 • Gordon Lyon (Fyodor)<fyodor@nmap.org> (http://insecure.org)
552 • Kris Katterjohn <katterjohn@gmail.com>
554 • Mixter <mixter@gmail.com>
556 The original Netcat was written by *Hobbit* <hobbit@avian.org>. While
558 Ncat isn't built on any code from the “traditional” Netcat (or any
559 other implementation), Ncat is most definitely based on Netcat in
560 spirit and functionality.
561
563 Ncat Copyright and Licensing
564 Ncat is (C) 2005–2022 Nmap Software LLC. It is distributed as free and
565 open source software under the same license terms as our Nmap software.
566 Precise terms and further details are available from
567 https://nmap.org/man/man-legal.html.
568 Creative Commons License for this Ncat Guide
570 This Ncat Reference Guide is (C) 2005–2022 Nmap Software LLC. It is
571 hereby placed under version 3.0 of the Creative Commons Attribution
572 License[1]. This allows you redistribute and modify the work as you
573 desire, as long as you credit the original source. Alternatively, you
574 may choose to treat this document as falling under the same license as
575 Ncat itself (discussed previously).
576 Source Code Availability and Community Contributions
578 Source is provided to this software because we believe users have a
579 right to know exactly what a program is going to do before they run it.
580 This also allows you to audit the software for security holes (none
581 have been found so far).
582 Source code also allows you to port Nmap (which includes Ncat) to new
584 platforms, fix bugs, and add new features. You are highly encouraged to
585 send your changes to <dev@nmap.org> for possible incorporation into the
586 main distribution. By sending these changes to Fyodor or one of the
587 Insecure.Org development mailing lists, it is assumed that you are
588 offering the Nmap Project (Nmap Software LLC) the unlimited,
589 non-exclusive right to reuse, modify, and relicense the code. Nmap will
590 always be available open source, but this is important because the
591 inability to relicense code has caused devastating problems for other
592 Free Software projects (such as KDE and NASM). We also occasionally
593 relicense the code to third parties as discussed in the Nmap man page.
594 If you wish to specify special license conditions of your
595 contributions, just say so when you send them.
596 No Warranty
598 This program is distributed in the hope that it will be useful, but
599 WITHOUT ANY WARRANTY; without even the implied warranty of
600 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Nmap
601 Public Source License for more details at https://nmap.org/npsl/, or in
602 the LICENSE file included with Nmap.
603 Inappropriate Usage
605 Ncat should never be installed with special privileges (e.g. suid
606 root). That would open up a major security vulnerability as other
607 users on the system (or attackers) could use it for privilege
608 escalation.
609 Third-Party Software
611 This product includes software developed by the Apache Software
612 Foundation[2]. A modified version of the Libpcap portable packet
613 capture library[3] is distributed along with Ncat. The Windows version
614 of Ncat utilized the Libpcap-derived Npcap library[4] instead. Certain
615 raw networking functions use the Libdnet[5] networking library, which
616 was written by Dug Song. A modified version is distributed with Ncat.
617 Ncat can optionally link with the OpenSSL cryptography toolkit[6] for
618 SSL version detection support. All of the third-party software
619 described in this paragraph is freely redistributable under BSD-style
620 software licenses.
621
623 1. Creative Commons Attribution License
624 http://creativecommons.org/licenses/by/3.0/
625 2. Apache Software Foundation
627 http://www.apache.org
628 3. Libpcap portable packet capture library
630 http://www.tcpdump.org
631 4. Npcap library
633 https://npcap.com
634 5. Libdnet
636 http://libdnet.sourceforge.net
637 6. OpenSSL cryptography toolkit
639 http://www.openssl.org
640Ncat 08/31/2022 NCAT(1)